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UGD Control SystemAitzaz HussainAgendaProcess SequenceAllen Bradley PLC 5/20 InstrumentsProcess Diagram

Basis for designNOx Reduction consumption 2*56 m3/h Design Flow Rate of UGD 172.3 m3/h System Design Temp 30 CMinimum Design Pressure 6 barThroughput Cycle 10 hoursRegeneration 2 hours ACFBackwasht= 10 minShut SeviOpen BWOOpen BWIStart Filtered Water PumpsSettlet= 5 minsStop Pumps; Close All valves

CONTD.Rinse t= 2 minsStart 1 filtered water pumpOpen FRO valveOpen SEVIStandby Stop Filtered Water PumpClose All valvesPre-Service Rinset= 2 minsOpen FROOpen SEVIStart 1 Filter Water PumpServicetime = Until DP reaches 500 mbarClose FROOpen SEVORegeneration of Anion & Cation Cation Compaction Open CWI/ DAI Valve of CationOpen WWO ValveOpen CWI for SACStart Regen Water Pump1.5% Acid Injectiont = 25 minClose CW-SAC of Acid Regen.Open BBI & BBOClose BBD ValveStart one Acid Regen Pumps3% Acid Injection t = 25 minsAcid Regen pump automatically rapms up to 3% requirementContd.Cation Displacementt = 19 minsStop Acid Regen PumpClose BBI and BBO valves of Acid RegenOpen BBD Valve of Acid RegenCation Settlement/ Anion CompactionOpen CWI of anion exchangerOpen WWO Valve for anionOpen CWI-SBAModulate Dilution Water Inlet of Caustic RegenModulate the Temperature Control Valve of Caustic RegenCation Standby/ 4% Caustic Injectiont = 7 minClose CWI of Caustic RegenOpen BBI and BBO valves of Caustic RegenClose BBD valve of Caustic RegenStart 1 Caustic Regen Pump

ContCation Rinse / 4% Caustic InjectOpen SEVI and FRO of CationStart filtered water supply pumpCation Standby / 4% Caustic Injectt = 20 minsStop Filtered water supplyClose SEVI & FRO on Cation ex.Cation Standby/ Anion Displacement t = 21 minsStop Caustic Regen pumpClose BBI, BBOOpen BBD valve of caustic regen Cont.Cation Standby / Anion Settlet = 10 minStop Regeneration water pumpCWI/DCI and WWO valves of anionCation Service/ Anion Rinset= 4 minsACF, Cation and degasifier set up for serviceOpen SEVI and FRO valves on anionStart Filtered Water PumpStart Degasified Water PumpCation Standby / Anion StandbyStop Filtered Water Pump SupplyStop Degasified Water Transfer PumpClose All Valves on Cation & AnionContdCation Service / Anion Preservice RinseApprox 5 minsOpen SEVI and SEVO on cationOpen SEVI and FRO on AnionOpen Conductivity Solenoid Valve on AnionStart 1 Filtered Water Supply PumpStart 1 Degasified Water Transfer PumpTrains rinse down until conductivity drops to 5 uS/cm for 45 consecutive secs.If above is true, start rinsing mix bedNormal Operation transferring water into Demin TankRegeneration of Mix BedBackwash : 10 minsSettle : 5 minsBlocking Flow/ Preheat : 13 mins4% Caustic Inject / 4% Acid Inject : 31 minsAcid Displacement / 4% Caustic Inject : 21 mins Acid Displacement / Caustic Displacement : 13 minsAcid Displacement / Caustic Rinse : 17 minsDrain Down : 10 minsAir Mix : 15 minsRefill : 8 minsRinse : 7 minsPreservice Rinse : 5 mins Service Neutralization SystemTo neutralize demineralization waste within allowable limitsRecycle initiates when pH is high or MMI commandIf pH ranges from 6-9 : Blow downIf pH > 9 : Acid Regen Valve Open & Start 1 Acid feed pumpIf pH < 6 : Caustic Regen Valve Open & Start 1 Caustic feed pump

PLC Allen Bradley 5/20 AB PLC 5/2016K Words memory512 I/Os (Any mix) or 512 I/Ps and 512 O/Ps (complementary)Two ChannelsSerial Comm.

FundamentalsHMI : Merely Interactive DisplayDynamic display status of assigned addressTakes user input PLC : BrainFetch, decode, execute, storeHMIPLCFIELDDevicesHMI @ Rousch

AB PLC 5/20

PLC Cycle Input ScanProgram ScanOutput ScanHousekeepingSTARTEach ladder rung is scanned using the data in the Input file. The resulting status (Logic being solved) is written to the Output file (Output Image).The status of external inputs (terminal block voltage) is written to the Input image (Input file).The Output Image data is transferred to the external output circuits, turning the output devices ON or OFF.Internal checks on memory, speed and operation. Service any communication requests, etc.Contd.Selector Switch RemoteProgramRun

DIP Switches

AlwaysOffI/O Modules

Rack Selection

MemoryRom Preprogramed with OSRAMContains user program being executedFresh Copies of updatesCurrent Status Generally battery back-up for storage of retentive dataEEPROMBack-up programProgram loaded from EEPROM if RAM is cleared or compromised

Number Systems - Revisit

PLC At Rousch2 Channels4 Racks (0-3)8 Slots Per Rack16 pt I/O modules 8 Points I/O Modules for Analog Outputs

Memory AddressingIdea is to inform the processor where the input or output point isImage Table Three Types in PLC-52 Slot Addressing 1 Slot Addressing Slot Addressing

2 Slot AddressingPhysically 2 Slots of I/O Module comprises of 1 Group16 Bits Per two slots or 8 bits per 1 slot per input or output moduleComplementary I/Os16 point I/O modules can only be used if they complement i.e if slot 0 is input, slot 1 must be output2 * 8-point I/O module can be used in any order1 * 16 point module if need to be used in order that does not complements then adjacent slot needs to be emptyAssigns one I/O Rack Number to 8 I/O groups

1 Slot AddressingOne group corresponds to one physical slotEach slot in chassis corresponds to 16 bit in input image table and 16 bit in output image table16 Point I/O Modules can be used in any combination32 Point I/O module can only be used as complementary pair8 Point Module would result in fewer I/Os Assign one I/O rack number to eight I/O Groups

Slot AddressingUtilizes Maximum I/Os2 Words (32 Bits) Corresponds to 1 slotTherefore, 32 pt I/O Modules can be connected in any orderAssigns 1 Rack number to 4 slotsUsage of 16 & 8 pt I/Os makes it under-utilized

Addressing Summary1 Slot Addressing is used at Rousch

Instruments Silica AnalyzerPrincipally an optical instrumentSample tube is placed between light source & photodectorAcidic Molybdate is reacted with Silica sampleThe absorption spectrum is observed & compared with a sample of molybdate silica solution with 0 ug/L silicaSamples are compared on basis of absorption and concentration is estimated

Conductivity AnalyzerDistilled water has low conductivity (0.5- 3uS/cm)Electrodes with fixed distance RTDElectrodes swap charges

pH ProbespH sensitive part is a glass bulb fused to glass tubeBuffered KCl at pH 7Silver Chloride wirePotential is measured between reference & sample